1. Technical Field
The present invention relates to a modified particle used for a catalyst component for addition polymerization; a catalyst component for addition polymerization; a catalyst for addition polymerization obtained using the same; and a process for producing an addition polymer.
2. Description of Related Arts
Olefin polymers such as polypropylene and polyethylene are superior in mechanical properties and chemical resistance and additionally superior in balance between properties and economies, and thereby they are extensively used in various molding fields.
These olefin polymers have hitherto been produced by polymerizing an olefin mainly using a conventional solid catalyst (multi-site catalyst) formed from a combination of the 4 group metal compound such as titanium trichloride or titanium tetrachloride and the 13 group metal compound typified by an organoaluminum compound.
In recent years, there has been proposed a process for producing an addition polymer comprising the step of polymerizing an olefin and the like using a so-called single site catalyst, which is a combination of a transition metal compound (for example, a metallocene complex and a non-metallocene complex) different from the solid catalyst component so far used, and an aluminoxane and the like. For example, a process comprising the step of using a combination of bis(cyclopentadienyl)zirconium dichloride and methylaluminoxane is reported in JP-A 58-19309. In addition, a combination of such a transition metal compound and a specific boron compound is also reported. For example, a process comprising the step of using bis(cyclopentadienyl)zirconium dimethyl and tri(n-butyl)ammonium tetraxis(pentafluorophenyl)borate is reported in JP-W1-502036. As known, an addition polymer obtained using such a single site catalyst is generally narrower in its molecular weight distribution than that obtained using the conventional solid catalyst (multi-site catalyst), and in the case of a copolymer, an addition polymer more homogeneous than that obtained using the conventional solid catalyst can be obtained because the comonomers are more homogeneously copolymerized.
An improvement of such catalysts for addition polymerization has been studied intensively, and, the kinds of metals used as a main catalyst component are broadly reported regarding each of Groups of the Periodic Table. For example, in Angew. Chem. Int. Ed. 38, 428 (1999), it is reported that metallocene complexes and non-metallocene compounds of metals of the Groups 3 to 13 are effective as a main catalyst component. On the other hand, as a co-catalyst component for activation used in combination of the metallocene complex or non-metallocene compound, aluminixanes and boron compounds belonging to the Group 13 occupy the center of its development. As a boron compound, a compound having an electron-withdrawing group on the boron atom, is generally effective.